(1) Field of the Invention
The present invention relates to a moving image pickup apparatus which can pick up an image at a high frame rate such as a high-speed imaging camera, a method for observing a moving image, a moving image observing program, and a computer-readable recording medium.
(2) Description of the Related Art
In order to photograph a change of an object, a high-speed imaging camera is used to serially pick up an image at a high frame rate. This apparatus displays frame image data picked up by an imaging unit at a predetermined imaging frame rate, on a display unit at a frame rate different from that at the time of imaging. For example, while an imaging cycle for an image is 1/30 second, that is, a frame rate is a standard speed of 30 fps (frame per second) in a usual video camera, a high frame rate such as 60 to 32000 fps can be set in the high-speed camera. When a moving image is recorded with the above high-speed camera, and a series of frame image data picked up at the high imaging frame rate is displayed on a display screen at a frame rate lower than that at the time of imaging, the series of image data of the motion of the object picked up with respect to each fine time can be observed in slow motion (refer to Japanese Unexamined Patent Publication Nos. 2009-141709 and 2009-100326).
Regarding the moving image picked up by the high-speed imaging apparatus, as the imaging frame rate increases, a playback time becomes extremely long compared to the imaging time, so that it is difficult to find out a desired picked-up image from enormous frame image data. Especially, as the high-speed camera is increased in speed, and the frame rate becomes high, that is, as the number of picked-up images per unit time increases, a moving image data amount to be analyzed becomes enormous, and the problem becomes more serious.
In addition, it is not easy to analyze an imaging target object contained in the image. For example, in a case where a product moving on a production line is serially photographed by the high-speed imaging apparatus to discover a cause of certain abnormality, when the time when abnormality is generated can be specified to some extent, it is only necessary to analyze an image around that time, but when the time is not known, the moving image has to be serially picked up for a long time, and a user has to visually confirm these images, so that the user has to visually confirm the images one by one so as to find out an abnormality generation process from the enormous image data containing the similar image, which forces the user to bear an extremely hard workload. At this time, when there is a certain index to make an analysis and the analysis is made based on the index, the workload can be considerably lightened.
Meanwhile, conventionally, by synchronizing an imaging operation with an input of another signal, that is, a synchronization signal such as a trigger signal to detect the generation of the abnormality, the moving image data is analyzed in the vicinity of the input timing of the trigger signal. However, according to this method, an additional sensor is needed to externally input the synchronization signal, and system architecture is needed to record the moving image by being linked with the synchronization signal. In addition, when the synchronization signal cannot be obtained, or a method to obtain it is not known, the above method cannot be used. Therefore, a simple method capable of obtaining an index of analysis with only the obtained image data has been needed.